PSYC 355
SPSS HOMEWORK: PAIRED-SAMPLES T TEST ASSIGNMENT INSTRUCTIONS
OVERVIEW
This assignment is designed to increase your statistical literacy and proficiency in conducting
and interpreting the paired-samples t test. You will be completing two paired-samples t tests in
SPSS, using data that are related to specific research scenarios in the behavioral sciences, such as
psychology, social work, and counseling. You will also be completing one Cumulative
Knowledge Question that will use an analysis learned in a previous week. Behind the scenes
knowledge of how this test is conducted is fundamental to being able to understand and apply
research in your related field to your practice. Additionally, SPSS skills are professionally
valuable, as it is one of the most commonly used statistical software packages in behavioral
science settings, both academic and professional.
INSTRUCTIONS
•This assignment includes three problem sets that contain research scenarios and related
questions.
•For each scenario, you will run an analysis in SPSS. The required product will include the
SPSS output, an APA-style Results section describing the results, and the appropriate
graph inserted as a Figure in APA style.
•For each scenario, you will create a new SPSS data file with the data from the problem
scenario. ALL variable names in your SPSS data files must include your initials, so that
they show up in your SPSS output and graph. For example, for someone with the initials
ABC creating a variable of memory scores, the variable could be named
“ABC_mem_scores” or “Mem_Scores_ABC”, etc.
•For all problems, interpret results based on an alpha level of = .05.
Please review the Watch: SPSS Homework Tutorial: The Paired samples t test in this module
for directions on how to run the statistical test, as well as the Watch: Results Sections for the
Paired-samples t test in APA Style, which includes a template for completing the APAstyle
Results sections for the paired-samples t test. The scenarios begin on the next page.
Problem Set 1: The paired-samples t test
Research Scenario: Research Scenario: A researcher is interested in how pairs of identical
twins score on the Verbal SAT in late high school. She collects scores from 11 twin pairs
(related subjects). The data appear in the table below.
Using this table, enter the data into a new SPSS data file and run a paired-samples t test
to test the claim that twins score differently from one another on the Verbal SAT.
Remember to put your initials within any and all variable names. Create a boxplot to show
the difference between the groups. Follow the directions below the table to complete this
part.
Twin 1 Twin 2
PSYC 355
630
577
698
409
499
659
617
683
702
590
502
621
503
723
450
474
701
634
656
723
684
650
1. Paste SPSS output. (10 pts)
2. Write an APA-style Results section based on your analysis. Include your boxplot as an
APA-style Figure, with figure number and title, as demonstrated in the Results Section
presentation. (Results = 12 pts; Figure = 8 pts)
Results
A repeated measures t test was conducted to test the claim that twins scored differently on the
verbal SAT. The test measure for the twins is the verbal SAT; we would assume the test is the
exact same for each twin. Figure 1 illustrates the score difference between twin 1 and twin 2.
The results show an insignificant difference between the group of Twin 1 (M = 596.9, SD = 94)
and the group of twin 2 (M = 619.9, SD = 99), t(10) = -1.26, p = .236. Because the result of the
test is insignificant, we fail to reject the null hypothesis.
PSYC 355
Figure 1
Score Difference between twins
CONTINUED ON NEXT PAGE
Problem Set 2: The paired-samples t test
Research Scenario: A clinical psychologist is studying whether keeping a gratitude journal
decreases self-reported depression in high-school females. She administers the Beck
Depression Inventory (BDI; Beck et al., 1961) and selects 10 female students with scores
greater than 20. She then gives each of these participants a journal with instructions on how to
keep a daily record of people, events, and other things that they are thankful for, After one
month of journaling, the participants complete the BDI a second time. The data are given in
the table below.
Using this table, enter the data into a new SPSS data file and run a paired-samples t test
to test the claim that keeping a gratitude journal decreases self-reported depression in
high-school females. Remember to put your initials within any and all variable names.
Create a boxplot to show the difference between the groups. Follow the directions below
the table to complete this part.
PSYC 355
BDI Scores Before
Journal
BDI Scores After
Journal
21
21
29
25
32
40
24
42
26
22
19
8
31
22
26
36
24
33
10
16
1. Paste SPSS output. (10 pts)
2. Write an APA-style Results section based on your analysis. Include your boxplot as an
APA-style Figure, with figure number and title, as demonstrated in the Results Section
presentation. (Results = 12 pts; Figure = 8 pts)
Results
A repeated measures t test was conducted to test the claim that high school female students who
keep a gratitude journal decreases self-reported depression. The test measure is the Beck
Depression Inventory (BDI; Beck et al., 1961). Figure 1 illustrates the score difference between
the BDI scores before journaling and after journaling. The results show a significant difference
before journaling (M = 28.2, SD = 7.6) and after journaling (M = 22.5, SD = 9.4), t(9) = 3.2, p
= .236. Because the result of the test is significant, we reject the null hypothesis that there is no
decrease in self-reported depression with the use of a journal.
PSYC 355
Figure 1
BDI scores before and after
Problem Set 3: Cumulative Knowledge Question
Research Scenario: An industrial/organizational psychologist at a large financial company
wants to compare the morale of employees who work in person vs. remotely. For his first
study, he chooses members of a team that handle customer complaints. He sends a survey
designed to measure employee morale to 12 team members in each group. The data appear in
the table below.
Using this table, enter the data into a new SPSS data file. Choose and run the correct
analysis (it will be one learned in a previous module) to determine whether there is a
difference in employee morale between the two groups. Choose and create the correct
graph that corresponds with this analysis. Remember to put your initials within any and all
variable names. Follow the directions below the table to complete this part.
In-person Team
Members
Remote Team
Members
39
32
40
23
42
18
27
23
19
30
17
27
12
20
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15 47
1. Paste SPSS output. (10 pts)
2. Write an APA-style Results section based on your analysis. Include the correct graph as
an APA-style Figure, with figure number and title, as demonstrated in the Results Section
presentation. (Results = 12 pts; Figure = 8 pts)
Results
An independent-sample t test was conducted to determine if there’s a difference in employee
morale employees who work in person and employees who work remotely. Group 1 of
employees work in person, while group 2 works remotely. Figure 1 illustrates the level of
employee morale. The results show an insignificant difference between the group that works in
person (M = 29.5, SD = 10.4) and the group that works remotely (M = 24.4, SD = 10.7), t(14)
= .97, p = .73. Because the result of the test is insignificant, we fail to reject the null hypothesis.
PSYC 355
Figure 1
Employee Morale
